I've been frustrated over this problem for hours now. I'm planning to sell a Gateway PC I have to a friend of mine, and she wanted it to be able to dual boot with XP and Vista. It has XP (Media Center Edition) preinstalled, which I kept as the XP she requested. I have partitioned out drives before, but the most experience I've had in allocating free space to a separate partition (rather than just wiping the drive) was using Vista's disk manager. Since I'm using XP as a starting point, I had to go with 3rd party software. I believe this is an older software by the way; PartitionMagic 8.0.
In PartitionMagic, I chose to divide out about half (90 GB) of the remaining free space on C: where XP is installed to a new NTFS partition labelled VISTA on the J: drive, which was the first drive letter listed to choose from. I didn't think of this until much later, but it's possible that the J: drive letter may have been previously assigned, since this PC has several readers for flash memory, as well as a DVD drive, and factory partition; though the factory partition must be fine, otherwise I wouldn't think the PC would boot up with the Gateway logo and all. I had just been somewhat under the assumption that PartitionMagic would at least give me some sort of warning if I were trying to create a partition on a drive letter that was in use, though later I was looking thru PartitionMagic's readme and it mentioned that you should take note of drive letters that are in use beforehand, which gave me that worry. After configuring these settings, I was prompted to reboot and I did so.
Upon the next reboot, I was greeted with a blue Windows XP splash screen and white text stating something along the lines of PartitionMagic doing its job and the progress, and then after suprisingly not too long (5 mins or so), another message came up that I now regret not reading very well and I was prompted to hit either "any key" or enter, and I did so. After that, the PC rebooted again and since then, I've been getting the black screen message that asks you "boot in safe mode", "last known good configuration", or "start Windows normally". It doesn't matter which of those options I choose; Windows will not boot at all now. The "Windows XP" loading screen with the progress bar will appear briefly and then it will be replaced by a message on a blue screen that flashes by so quickly, I can't read a word of it. Then the PC will reboot itself again, and it will continue doing this in a loop.
I've done plenty of Google searches and can't find any answers. I can't use the PartitionMagic "recovery discs" because no PC I am working with has a floppy drive. Recently I configured BIOS to boot from CD-ROM first and put in my own XP operating system disc to use Windows Recovery Console. The J: drive apparently does not exist, and therefore cannot be formatted. The C: drive has the same amount of space as it did beforehand, but now its filesystem is apparently "Unknown" rather than NTFS. Using the "fixboot" command makes no change.
I really do need to figure out how to get this PC back to its original working state and be able to put Vista on another partition very soon because of the promised sale. I'd prefer to only have to wipe the whole drive as a last resort because I spent a couple of hours beforehand uninstalling manufacturer placed free trial software and installing some preferred software as a favor since this is for a friend. From what I can tell, everything concerning the XP partition is as it should be, except something strange is going on with the filesystem and booting process. I'm ok with working in BIOS or any sort of command prompt, burning programs to disc, or even placing programs on a flash drive.